#### Answer

t = 0.75s

#### Work Step by Step

In the previous section we found that a = $(6-8t)i $
Therefore, to find when the acceleration is 0, we plug in 0 for a and solve for the t at which this occurs.
The j and k components are always 0 so we need only worry about the i component. The magnitude of this vector is given by:
$magnitude = \sqrt(i^2 + j^2 +k^2) $
where i, j, and k represent the i, j, and k components respectively
Therefore, we have
$ magnitude = \sqrt((6-8t)^2) $ which is just 6-8t
Therefore we can solve for when a = 0:
$ 0 = 6-8t $ so then t = 0.75s